Improvement-in diex  for cutting sqrew-threaos



Joan J. GRANT, or cnnnnrrnnn, Massacnnsnrrs.-

iWitRVEWIENT-IN DlES FOR CUT-Titti@ SQREWTHREADS.

lSpecification forming part of Letters Patent No. lll4li'r,h33, dated June N2l, 1873; application tiled April 18,' 1873.

To all whom it may concern:

Be it known that I, JOHN J. GRANT, of Greenlield, county of Franklin and State of llllassachusetts, have invented icertain Imlproven]ents in Dies for Screw-Cutting.

@United States.

rllhis imgention consists in the arrangement, within the die stock orholder and between the dies, of cones and screws for adjusting uid setting out the dies, such screws operatiiig in combination with external setscrews to obtain a perfect and secure adjustment of the dies.

In the accompanying drawing, which illus tratesy the invention, Figure l is a plan of the front side of the die. Fig. 2 is a plan ot' the back side of the die. Fig. 3 is atra-nsverse section of the same taken at the dotted line w :c in Fig. 1. Fig. e is another transverse section taken in the line y y in Fig. 1.` Fig. 5 lillustrates the screw, upon the top of ,which is cut the frustum of a cone as arranged with the screw in the front ofthe die.

In the drawing referred to, A designates the die stock or holder having in its face a cavity, a, represented of circular form, for the reception of the dies B B. In the bottom of said recess is hole, b, that extends through Vthe stock to permit the passage ot' the cut screw from the die. The dies B B are ot' a size and form externally to fit easily into the cavity a,

and are provided with recesses c-c and a n on their` opposite and adjacent faces at the sides of the cutting portions el d. The said recesses c c in the back` part of the die are of such a shape as to receive the conical frustums h l1.,

in, with the stock and dies and setscrews when operating together as and for the purwhile the recesses a n are ot' such ashape as to receive the outer screws s s. The conical frust-ums are adjusted in position by means ofthe screwswhich are formed upon their bases and which pass through internal screws in the stock. The outer screws s s work in intei-nal screws cutin the inner screws, as shown clearly in the drawing, in such a manner as to clamp the die iirmly down. D D are screws that-form the external adjustment. They screw into the sides ofthe stock A and bear against the middle portions oi' the exterior or circular portions of the dies B B;

To adjust the dies to enable screws of differ; entdepths and sizes to be out, the screws which operate the conicai frustums h h are screwed either further into the stock to separate the dies, or from the stock to allow. the set-screws D D to force them toward each other. The set-screws D D are screwed up to hold the dies in any'position lto which they are adjusted, and the outer screws s s clamp the dies down firmly to the bottom of the cavity in the stock':

Having thus described the construction and operation of my invention, I claim and desire to secure by Letters Patent- 1. The combination of the conical frustums upon which are formed screws working in internal screws cut in the stock, the outer screws working' in internal threads cut in the said conical frustums, `and the dies provided with recesses, all operatin g together a's and for the purposes described.

2. The combination of the interposed con' ical frustums, and outer screws working thereposes described.

In testimony that I claim the foregoing I have hereunto set my hand and seal this 10th day of April, 1873.

. J'GHN J. GRANT.

Y Witnesses L. L. LUEY, WENDELL P. Devis. 

